Hydraulic radial piston machines

Abstract

A hydraulic reciprocating piston machine having a housing, a rotatable cylinder-barrel having a series of cylinders and each cylinder containing a piston which is operatively connected to a reaction member. The reaction member being urged by the forces created from those pistons subject to the pressure phase of the working cycle toward and against an abutment-member. The reaction member is purposefully provided with a limited freedom for movement with the housing, and the action of the pistons forces in urging the reaction member towards the abutment-member provides for a substantial reduction in the normal vibration of the reaction member without binding between the adjacent bearing surfaces.

We claim: 
     
       1. A radial piston machine comprising a housing, a rotatable cylinder-barrel disposed in said housing and provided with a series of cylinders each containing a piston, an annular track-ring surrounding said cylinder-barrel such that the pistons in said cylinders bear on said track-ring, said track-ring being mounted for pivotal movement in a radial plane about an eccentric axis parallel to the axis of rotation of said cylinder-barrel, and abutment-surfaces for controlling contact between said annular track-ring and the interior of said housing, said abutment-surfaces comprising a concave first part-cylindrical bearing-surface on the interior of said housing, and a complementary convex second part-cylindrical bearing-surface on an exterior portion of said track-ring, said first and second bearing-surfaces describing cylinders having a common axis coincident with said eccentric axis. 
     
     
       2. A radial piston machine according to claim 1 wherein said abutment-surfaces are arranged to resist the reaction force of said pistons in urging said track-ring in a direction towards said abutment-surfaces, and where said track-ring has a degree of radial freedom to move relative to the radial position of said cylinder-barrel. 
     
     
       3. A radial piston machine according to claim 2 and including a pintle-valve or equivalent fluid distribution means having a pair of arcuate-slots for fluid coupling with said cylinders of said cylinder-barrel, said pair of arcuate-slots comprising a low-pressure arcuate-slot and a high-pressure arcuate-slot and where said high-pressure arcuate-slot is the slot positioned nearest to said abutment-surfaces. 
     
     
       4. A radial piston machine according to claim 3 and including track-ring actuating means operatively connected to said track-ring and positioned adjacent to said abutment-surfaces. 
     
     
       5. A radial piston machine according to claim 4 wherein the said track-ring actuating means comprises at least one hydraulic-ram. 
     
     
       6. A radial piston machine according to claim 4 wherein said track-ring actuating means comprises a strut-member and where said track-ring is held in an eccentric position relative to said housing by said strut-member when said strut-member is in a partially deformed condition, and where rising pressure in said cylinders causes an increase in the deformation of said strut-member and a corresponding decrease in the eccentricity of said track-ring. 
     
     
       7. A radial piston machine according to claim 4 wherein said housing comprises two shells connectable together along a parting-plane coincident with the said rotating axis of said cylinder-barrel, and where said abutment-surfaces are disposed to both sides of said parting-plane. 
     
     
       8. A radial piston machine according to claim 1 wherein said eccentric axis has a limited ability to float in a direction transverse to the rotational axis of said machine to allow progressive engagement of said abutment-surfaces as the pressure level in said machine rises. 
     
     
       9. A radial piston machine according to claim 1 wherein a slot formed in the interior of said housing and adjacent to said eccentric axis acts to provide a guidance surface for the radial movement of said track-ring. 
     
     
       10. A radial piston machine according to claim 1 wherein a slot formed in the periphery of said track-ring and adjacent to said eccentric axis acts to provide a guidance surface for the radial movement of said track-ring. 
     
     
       11. A radial piston machine according to claim 1 including means for urging said track-ring and said abutment-surfaces together and resisting the reaction force of said pistons on said track-ring. 
     
     
       12. A radial piston machine according to claim 11 wherein those said pistons which at any instant are subjected to the pressure phase in the working cycle are acting on said track-ring to form the said urging means. 
     
     
       13. A radial piston machine according to claim 12 wherein the said urging means comprise resilient means or fluid means acting between said track-ring and said housing. 
     
     
       14. A radial piston machine according to claim 1 wherein said eccentric axis is disposed to one side of said rotation axis of said machine and the said abutment-surfaces are disposed on the opposite side. 
     
     
       15. A radial piston machine according to claim 1 wherein fluid lubrication grooves or hydrostatic bearings are provided on said abutment-surfaces. 
     
     
       16. A radial piston machine according to claim 1 wherein the said exterior portion covers at most 30% of the total circumferential length of said track-ring and has a surface area of at least two times greater than the surface area of one of the said pistons. 
     
     
       17. A radial piston machine according to claim 1 wherein mechanical biasing means are provided for pre-loading said abutment-surfaces together. 
     
     
       18. A radial piston machine according to claim 17 wherein said mechanical biasing means comprise a wedge-member or a strut-member. 
     
     
       19. A radial piston machine according to claim 1 wherein said abutment-surfaces are arranged to resist the reaction force of said pistons in urging said track-ring in a direction towards said abutment-surfaces, said track-ring having first and second degrees of freedom for motion relative to said cylinder-barrel, pivotal movement for the first freedom of motion, transverse movement to the said axis of rotating of said cylinder-barrel for the second freedom of motion. 
     
     
       20. A radial piston machine according to claim 1 wherein an arc "R" for defining the said exterior portion of said track-ring diverges from that arc "R2" defining a circle about the said axis of rotation of said machine. 
     
     
       21. A radial piston machine including a housing, a rotatable cylinder-barrel disposed in said housing and provided with a series of cylinders each containing a piston, an annular track-ring surrounding said cylinder-barrel such that the pistons in said cylinders can bear on said track-ring and abutment means disposed radially adjacent said track-ring, pivoting means for mounting said track-ring for allowing its radial position to be varied relative to the radial position of said cylinder-barrel for variation in the fluid displacement of said pistons and where said track-ring is further provided with a limited ability to float relative to said pivoting means towards said abutment means, and where said abutment means act to resist the reaction force of said pistons on said track-ring. 
     
     
       22. A radial piston machine as claimed in claim 21 and including a pintle-valve or equivalent fluid distribution means having a pair of arcuate-slots for fluid coupling with said cylinders of said cylinder-barrel, said pair of arcuate-slots comprising a low-pressure arcuate-slot and a high-pressure arcuate-slot and where said high-pressure arcuate-slot is the slot positioned nearest to said abutment means. 
     
     
       23. A radial piston machine including a housing, a rotatable cylinder-barrel disposed in said housing and provided with a series of cylinders each containing a piston, an annular track-ring surrounding said cylinder-barrel such that the pistons in said cylinders can bear on said track-ring and abutment means disposed radially adjacent said track-ring, said track-ring journalled on a pin supported in said housing and pivotable about said pin for allowing its radial position to be varied relative to the radial position of said cylinder-barrel for variation in the fluid displacement of said pistons and where said track-ring is provided with a limited ability to float towards said abutment means for resisting the reaction force of said pistons on said track-ring, a pintle-valve or equivalent fluid distribution means including a pair of arcuate-slots for fluid coupling with said cylinders of said cylinder-barrel, said pair of arcuate-slots comprising a low-pressure arcuate-slot and a high-pressure arcuate-slot, a deformable strut-member having a first end and a second end, said first end operatively connected to said housing and said second end operatively connected to said track-ring in a position nearest to said high-pressure arcuate-slot, and wherein said track-ring is held in an eccentric position relative to said housing by said strut-member when said strut-member is in a partially deformed condition, and where rising pressure inside said cylinders causes an increase in the deformation of said strut-member and a corresponding decrease in the eccentricity of said track-ring, said track-ring being in operational engagement with said abutment means as said strut-member deforms. 
     
     
       24. A reciprocating piston machine including a housing, a rotatable cylinder-barrel disposed in said housing and provided with a series of cylinders each containing a piston, the pistons in said cylinders being operatively connected to a surrounding piston reaction member, and where said piston reaction member is positioned inwardly adjacent to an abutment-member and where said piston reaction member is provided with freedom to float in the direction of said abutment-member, said abutment-member being arranged to resist the action of those said pistons subjected to the pressure phase in the working cycle in urging said piston reaction member in a direction towards said abutment-member, a pintle-valve or equivalent fluid distribution means including a pair of arcuate-slots for fluid coupling with said cylinders of said cylinder-barrel, said pair of arcuate-slots comprising a low-pressure arcuate-slot and a high-pressure arcuate-slot, a deformable strut-member having a first end and a second end, said first end operatively connected to said housing and said second end operatively connected to said piston reaction member in a position nearest to said high-pressure arcuate-slot, and wherein said piston reaction member is held in an eccentric position relative to said housing by said strut-member when said strut-member is in a partially deformed condition to cause maximum reciprocation of said pistons, and where rising pressure inside said cylinders causes an increase in the deformation of said strut-member and a corresponding decrease in the amount of reciprocation of said pistons, said piston reaction member being in operational engagement with said abutment-member as said strut-member deforms. 
     
     
       25. A reciprocating piston machine including a housing, a rotatable cylinder-barrel disposed in said housing and provided with a series of cylinders each containing a piston, the pistons in said cylinders being operatively connected to a surrounding piston reaction member and an abutment-member disposed radially adjacent said piston reaction member, said piston reaction member being journalled on a pin supported in said housing and pivotable about said pin for allowing its radial position to be varied relative to the radial position of said cylinder-barrel for variation of the reciprocating stroke of said pistons and where said piston reaction member is provided with a limited ability to float towards said abutment-member for resisting the reaction force of said pistons on said piston reaction member, a pintle-valve or equivalent fluid distribution means including a pair of arcuate-slots for fluid coupling with said cylinders of said cylinder-barrel, said pair of arcuate-slots comprising a low-pressure arcuate-slot and a high-pressure arcuate-slot, a deformable strut-member having a first end and a second end, said first end operatively connected to said housing and said second end operatively connected to said piston reaction member in a position nearest to said high-pressure arcuate-slot, and wherein said piston reaction member is held in an eccentric position relative to said housing by said strut-member when said strut-member is in a partially deformed condition to cause maximum reciprocation of said pistons, and where rising pressure inside said cylinders causes an increase in the deformation of said strut-member and a corresponding decrease in the amount of reciprocation of said pistons, said piston reaction member being in operational engagement with said abutment-member as said strut-member deforms.